Exhaust System Overview Exhaust Connections

CHAPTER II LITERATURE REVIEW

2.1 Introduction

The literature review is based on the physics of the project undertaken here, concentrating on the introduction on the exhaust system, normal mode analysis and vibration theory. The literature review continues with the discussion on the information related with how to conduct the experiment and software simulation for this research.

2.2 Exhaust System

2.2.1 Exhaust System Overview

The parts of an exhaust system are shown in Figure 2.1. The main parts are the engine pipe, resonator, intermediate pipe, muffler and the tailpipe. The engine pipe is attached to the exhaust manifold outlet by the flange. Brackets and mountings on the various parts support the system in relation to the engine and the body of the vehicle. The exhaust system has flexible mountings that prevent exhaust vibration from being transmitted to the body. They also allow for thermal expansion of the system. The exhaust pipes are design with various shapes to suit the location of the engine and the type and design of the bodywork of the particular vehicle. An example of an exhaust installation is shown in Figure 2.2. The system shown has an exhaust manifold with separate branches joined to a flange. Twin engine pipes are used between the manifold and the intermediate pipe. Two mufflers are fitted, one in the middle and the other at the rear end of the system. Figure 2.1 : Exhaust system components Source : [1] Figure 2.2 : Components of an exhaust system Source : [1]

2.2.2 Exhaust Connections

In some cases, the exhaust pipes and mufflers are joined by fitting the end of one pipe into another which shown in Figure 2.3. A clamp is then used to hold the parts firmly together. In other cases, connections between the parts of the system are made with flanged joints. Figure 2.3 : Joint on mufflers and exhaust pipe Source : [1] Figure 2.4 shows a joint between the exhaust manifold flange and the engine pipe flange. Two holes in the manifold flange align with the two corresponding holes in the engine pipes. The exhaust gas from two of the engine’s cylinders is fed into each engine pipe. A gasket of heat-resistant material is fitted between the two flanges. Figure 2.4 : Exhaust manifold to engine pipe connection Source : [1] Figure 2.5 shows one type of connection that is used between the engine pipe and the intermediate pipe. This is semi flexible designs that assist with alignments of the pipes and also helps to reduce vibrations. In this joint, the sealing ring 3 between the two pipes has a spherical end, which fits into a similarly shaped end of the exhaust pipe 4. The two bolts 7 that hold the flanges 2 and 5 of the two pipes together are fitted with springs 6, so that the sealing ring is held firmly onto its seat. This provides a joint that is firm, but not rigid. Figure 2.5 : Semiflexible connection in exhaust system 1 mounting-bracket assembly, 2 flange on engine pipe, 3 sealing ring, 4 conical seat, 5 flange on intermediate pipe, 6 spring, 7 flange bolt Source: [1]

2.2.3 Exhaust with Extractors